/*-------------------------------------------------------------------------
 *
 * setrefs.c
 *      Post-processing of a completed plan tree: fix references to subplan
 *      vars, compute regproc values for operators, etc
 *
 * Portions Copyright (c) 2012-2014, TransLattice, Inc.
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *      src/backend/optimizer/plan/setrefs.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/transam.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/tlist.h"
#include "tcop/utility.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#ifdef PGXC
#include "pgxc/planner.h"
#endif


typedef struct
{
    Index        varno;            /* RT index of Var */
    AttrNumber    varattno;        /* attr number of Var */
    AttrNumber    resno;            /* TLE position of Var */
} tlist_vinfo;

typedef struct
{
    List       *tlist;            /* underlying target list */
    int            num_vars;        /* number of plain Var tlist entries */
    bool        has_ph_vars;    /* are there PlaceHolderVar entries? */
    bool        has_non_vars;    /* are there other entries? */
	bool		has_conv_whole_rows;	/* are there ConvertRowtypeExpr
										 * entries encapsulating a whole-row
										 * Var? */
    tlist_vinfo vars[FLEXIBLE_ARRAY_MEMBER];    /* has num_vars entries */
} indexed_tlist;

typedef struct
{
    PlannerInfo *root;
    int            rtoffset;
} fix_scan_expr_context;

typedef struct
{
    PlannerInfo *root;
    indexed_tlist *outer_itlist;
    indexed_tlist *inner_itlist;
    Index        acceptable_rel;
    int            rtoffset;
} fix_join_expr_context;

typedef struct
{
    PlannerInfo *root;
    indexed_tlist *subplan_itlist;
    Index        newvarno;
    int            rtoffset;
} fix_upper_expr_context;

typedef struct
{
    PlannerGlobal *glob;
    indexed_tlist *base_itlist;
    int               rtoffset;
    Index           relid;
} fix_remote_expr_context;

/*
 * Check if a Const node is a regclass value.  We accept plain OID too,
 * since a regclass Const will get folded to that type if it's an argument
 * to oideq or similar operators.  (This might result in some extraneous
 * values in a plan's list of relation dependencies, but the worst result
 * would be occasional useless replans.)
 */
#define ISREGCLASSCONST(con) \
    (((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
     !(con)->constisnull)

#define fix_scan_list(root, lst, rtoffset) \
    ((List *) fix_scan_expr(root, (Node *) (lst), rtoffset))

static void add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing);
static void flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte);
static bool flatten_rtes_walker(Node *node, PlannerGlobal *glob);
static void add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte);
static Plan *set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset);
static Plan *set_indexonlyscan_references(PlannerInfo *root,
                             IndexOnlyScan *plan,
                             int rtoffset);
static Plan *set_subqueryscan_references(PlannerInfo *root,
                            SubqueryScan *plan,
                            int rtoffset);
static bool trivial_subqueryscan(SubqueryScan *plan);
static void set_foreignscan_references(PlannerInfo *root,
                           ForeignScan *fscan,
                           int rtoffset);
static void set_customscan_references(PlannerInfo *root,
                          CustomScan *cscan,
                          int rtoffset);
static Node *fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset);
static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
static void set_join_references(PlannerInfo *root, Join *join, int rtoffset);
static void set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset);
static Node *convert_combining_aggrefs(Node *node, void *context);
static void set_dummy_tlist_references(Plan *plan, int rtoffset);
static indexed_tlist *build_tlist_index(List *tlist);
static Var *search_indexed_tlist_for_var(Var *var,
                             indexed_tlist *itlist,
                             Index newvarno,
                             int rtoffset);
static Var *search_indexed_tlist_for_non_var(Expr *node,
                                 indexed_tlist *itlist,
                                 Index newvarno);
static Var *search_indexed_tlist_for_sortgroupref(Expr *node,
                                      Index sortgroupref,
                                      indexed_tlist *itlist,
                                      Index newvarno);
static List *fix_join_expr(PlannerInfo *root,
              List *clauses,
              indexed_tlist *outer_itlist,
              indexed_tlist *inner_itlist,
              Index acceptable_rel, int rtoffset);
static Node *fix_join_expr_mutator(Node *node,
                      fix_join_expr_context *context);
static Node *fix_upper_expr(PlannerInfo *root,
               Node *node,
               indexed_tlist *subplan_itlist,
               Index newvarno,
               int rtoffset);
static Node *fix_upper_expr_mutator(Node *node,
                       fix_upper_expr_context *context);
static List *set_returning_clause_references(PlannerInfo *root,
                                List *rlist,
                                Plan *topplan,
                                Index resultRelation,
                                int rtoffset);
static bool extract_query_dependencies_walker(Node *node,
                                  PlannerInfo *context);
static bool is_converted_whole_row_reference(Node *node);

#ifdef XCP
static void set_remotesubplan_references(PlannerInfo *root, Plan *plan, int rtoffset);
#endif

/*****************************************************************************
 *
 *        SUBPLAN REFERENCES
 *
 *****************************************************************************/

/*
 * set_plan_references
 *
 * This is the final processing pass of the planner/optimizer.  The plan
 * tree is complete; we just have to adjust some representational details
 * for the convenience of the executor:
 *
 * 1. We flatten the various subquery rangetables into a single list, and
 * zero out RangeTblEntry fields that are not useful to the executor.
 *
 * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
 *
 * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
 * subplans.
 *
 * 4. Aggrefs in Agg plan nodes need to be adjusted in some cases involving
 * partial aggregation or minmax aggregate optimization.
 *
 * 5. PARAM_MULTIEXPR Params are replaced by regular PARAM_EXEC Params,
 * now that we have finished planning all MULTIEXPR subplans.
 *
 * 6. We compute regproc OIDs for operators (ie, we look up the function
 * that implements each op).
 *
 * 7. We create lists of specific objects that the plan depends on.
 * This will be used by plancache.c to drive invalidation of cached plans.
 * Relation dependencies are represented by OIDs, and everything else by
 * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
 * Currently, relations and user-defined functions are the only types of
 * objects that are explicitly tracked this way.
 *
 * 8. We assign every plan node in the tree a unique ID.
 *
 * We also perform one final optimization step, which is to delete
 * SubqueryScan plan nodes that aren't doing anything useful (ie, have
 * no qual and a no-op targetlist).  The reason for doing this last is that
 * it can't readily be done before set_plan_references, because it would
 * break set_upper_references: the Vars in the subquery's top tlist
 * wouldn't match up with the Vars in the outer plan tree.  The SubqueryScan
 * serves a necessary function as a buffer between outer query and subquery
 * variable numbering ... but after we've flattened the rangetable this is
 * no longer a problem, since then there's only one rtindex namespace.
 *
 * set_plan_references recursively traverses the whole plan tree.
 *
 * The return value is normally the same Plan node passed in, but can be
 * different when the passed-in Plan is a SubqueryScan we decide isn't needed.
 *
 * The flattened rangetable entries are appended to root->glob->finalrtable.
 * Also, rowmarks entries are appended to root->glob->finalrowmarks, and the
 * RT indexes of ModifyTable result relations to root->glob->resultRelations.
 * Plan dependencies are appended to root->glob->relationOids (for relations)
 * and root->glob->invalItems (for everything else).
 *
 * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
 * to process targetlist and qual expressions.  We can assume that the Plan
 * nodes were just built by the planner and are not multiply referenced, but
 * it's not so safe to assume that for expression tree nodes.
 */
Plan *
set_plan_references(PlannerInfo *root, Plan *plan)
{
    PlannerGlobal *glob = root->glob;
    int            rtoffset = list_length(glob->finalrtable);
    ListCell   *lc;

    /*
     * Add all the query's RTEs to the flattened rangetable.  The live ones
     * will have their rangetable indexes increased by rtoffset.  (Additional
     * RTEs, not referenced by the Plan tree, might get added after those.)
     */
    add_rtes_to_flat_rtable(root, false);

    /*
     * Adjust RT indexes of PlanRowMarks and add to final rowmarks list
     */
    foreach(lc, root->rowMarks)
    {
        PlanRowMark *rc = lfirst_node(PlanRowMark, lc);
        PlanRowMark *newrc;

        /* flat copy is enough since all fields are scalars */
        newrc = (PlanRowMark *) palloc(sizeof(PlanRowMark));
        memcpy(newrc, rc, sizeof(PlanRowMark));

        /* adjust indexes ... but *not* the rowmarkId */
        newrc->rti += rtoffset;
        newrc->prti += rtoffset;

        glob->finalrowmarks = lappend(glob->finalrowmarks, newrc);
    }

    /* Now fix the Plan tree */
    return set_plan_refs(root, plan, rtoffset);
}

/*
 * Extract RangeTblEntries from the plan's rangetable, and add to flat rtable
 *
 * This can recurse into subquery plans; "recursing" is true if so.
 */
static void
add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing)
{// #lizard forgives
    PlannerGlobal *glob = root->glob;
    Index        rti;
    ListCell   *lc;

    /*
     * Add the query's own RTEs to the flattened rangetable.
     *
     * At top level, we must add all RTEs so that their indexes in the
     * flattened rangetable match up with their original indexes.  When
     * recursing, we only care about extracting relation RTEs.
     */
    foreach(lc, root->parse->rtable)
    {
        RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);

        if (!recursing || rte->rtekind == RTE_RELATION)
            add_rte_to_flat_rtable(glob, rte);
    }

    /*
     * If there are any dead subqueries, they are not referenced in the Plan
     * tree, so we must add RTEs contained in them to the flattened rtable
     * separately.  (If we failed to do this, the executor would not perform
     * expected permission checks for tables mentioned in such subqueries.)
     *
     * Note: this pass over the rangetable can't be combined with the previous
     * one, because that would mess up the numbering of the live RTEs in the
     * flattened rangetable.
     */
    rti = 1;
    foreach(lc, root->parse->rtable)
    {
        RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);

        /*
         * We should ignore inheritance-parent RTEs: their contents have been
         * pulled up into our rangetable already.  Also ignore any subquery
         * RTEs without matching RelOptInfos, as they likewise have been
         * pulled up.
         */
        if (rte->rtekind == RTE_SUBQUERY && !rte->inh &&
            rti < root->simple_rel_array_size)
        {
            RelOptInfo *rel = root->simple_rel_array[rti];

            if (rel != NULL)
            {
                Assert(rel->relid == rti);    /* sanity check on array */

                /*
                 * The subquery might never have been planned at all, if it
                 * was excluded on the basis of self-contradictory constraints
                 * in our query level.  In this case apply
                 * flatten_unplanned_rtes.
                 *
                 * If it was planned but the result rel is dummy, we assume
                 * that it has been omitted from our plan tree (see
                 * set_subquery_pathlist), and recurse to pull up its RTEs.
                 *
                 * Otherwise, it should be represented by a SubqueryScan node
                 * somewhere in our plan tree, and we'll pull up its RTEs when
                 * we process that plan node.
                 *
                 * However, if we're recursing, then we should pull up RTEs
                 * whether the subquery is dummy or not, because we've found
                 * that some upper query level is treating this one as dummy,
                 * and so we won't scan this level's plan tree at all.
                 */
                if (rel->subroot == NULL)
                    flatten_unplanned_rtes(glob, rte);
                else if (recursing ||
                         IS_DUMMY_REL(fetch_upper_rel(rel->subroot,
                                                      UPPERREL_FINAL, NULL)))
                    add_rtes_to_flat_rtable(rel->subroot, true);
            }
        }
        rti++;
    }
}

/*
 * Extract RangeTblEntries from a subquery that was never planned at all
 */
static void
flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte)
{
	/* Use query_tree_walker to find all RTEs in the parse tree */
	(void) query_tree_walker(rte->subquery,
							 flatten_rtes_walker,
							 (void *) glob,
							 QTW_EXAMINE_RTES_BEFORE);
}

static bool
flatten_rtes_walker(Node *node, PlannerGlobal *glob)
{
	if (node == NULL)
		return false;
	if (IsA(node, RangeTblEntry))
	{
		RangeTblEntry *rte = (RangeTblEntry *) node;

		/* As above, we need only save relation RTEs */
		if (rte->rtekind == RTE_RELATION)
			add_rte_to_flat_rtable(glob, rte);
		return false;
	}
	if (IsA(node, Query))
	{
		/* Recurse into subselects */
		return query_tree_walker((Query *) node,
								 flatten_rtes_walker,
								 (void *) glob,
								 QTW_EXAMINE_RTES_BEFORE);
	}
	return expression_tree_walker(node, flatten_rtes_walker,
								  (void *) glob);
}

/*
 * Add (a copy of) the given RTE to the final rangetable
 *
 * In the flat rangetable, we zero out substructure pointers that are not
 * needed by the executor; this reduces the storage space and copying cost
 * for cached plans.  We keep only the ctename, alias and eref Alias fields,
 * which are needed by EXPLAIN, and the selectedCols, insertedCols and
 * updatedCols bitmaps, which are needed for executor-startup permissions
 * checking and for trigger event checking.
 */
static void
add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte)
{
    RangeTblEntry *newrte;

    /* flat copy to duplicate all the scalar fields */
    newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
    memcpy(newrte, rte, sizeof(RangeTblEntry));

    /* zap unneeded sub-structure */
    newrte->tablesample = NULL;
    newrte->subquery = NULL;
    newrte->joinaliasvars = NIL;
    newrte->functions = NIL;
    newrte->tablefunc = NULL;
    newrte->values_lists = NIL;
    newrte->coltypes = NIL;
    newrte->coltypmods = NIL;
    newrte->colcollations = NIL;
    newrte->securityQuals = NIL;

    glob->finalrtable = lappend(glob->finalrtable, newrte);

    /*
     * Check for RT index overflow; it's very unlikely, but if it did happen,
     * the executor would get confused by varnos that match the special varno
     * values.
     */
    if (IS_SPECIAL_VARNO(list_length(glob->finalrtable)))
        ereport(ERROR,
                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                 errmsg("too many range table entries")));

    /*
     * If it's a plain relation RTE, add the table to relationOids.
     *
     * We do this even though the RTE might be unreferenced in the plan tree;
     * this would correspond to cases such as views that were expanded, child
     * tables that were eliminated by constraint exclusion, etc. Schema
     * invalidation on such a rel must still force rebuilding of the plan.
     *
     * Note we don't bother to avoid making duplicate list entries.  We could,
     * but it would probably cost more cycles than it would save.
     */
    if (newrte->rtekind == RTE_RELATION)
        glob->relationOids = lappend_oid(glob->relationOids, newrte->relid);
}

/*
 * set_plan_refs: recurse through the Plan nodes of a single subquery level
 */
static Plan *
set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
{// #lizard forgives
    ListCell   *l;

    if (plan == NULL)
        return NULL;

    /* Assign this node a unique ID. */
    plan->plan_node_id = root->glob->lastPlanNodeId++;

    /*
     * Plan-type-specific fixes
     */
    switch (nodeTag(plan))
    {
        case T_SeqScan:
            {
                SeqScan    *splan = (SeqScan *) plan;

                splan->scanrelid += rtoffset;
                splan->plan.targetlist =
                    fix_scan_list(root, splan->plan.targetlist, rtoffset);
                splan->plan.qual =
                    fix_scan_list(root, splan->plan.qual, rtoffset);
            }
            break;
        case T_SampleScan:
            {
                SampleScan *splan = (SampleScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->tablesample = (TableSampleClause *)
                    fix_scan_expr(root, (Node *) splan->tablesample, rtoffset);
            }
            break;
        case T_IndexScan:
            {
                IndexScan  *splan = (IndexScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->indexqual =
                    fix_scan_list(root, splan->indexqual, rtoffset);
                splan->indexqualorig =
                    fix_scan_list(root, splan->indexqualorig, rtoffset);
                splan->indexorderby =
                    fix_scan_list(root, splan->indexorderby, rtoffset);
                splan->indexorderbyorig =
                    fix_scan_list(root, splan->indexorderbyorig, rtoffset);
            }
            break;
        case T_IndexOnlyScan:
            {
                IndexOnlyScan *splan = (IndexOnlyScan *) plan;

                return set_indexonlyscan_references(root, splan, rtoffset);
            }
            break;
        case T_BitmapIndexScan:
            {
                BitmapIndexScan *splan = (BitmapIndexScan *) plan;

                splan->scan.scanrelid += rtoffset;
                /* no need to fix targetlist and qual */
                Assert(splan->scan.plan.targetlist == NIL);
                Assert(splan->scan.plan.qual == NIL);
                splan->indexqual =
                    fix_scan_list(root, splan->indexqual, rtoffset);
                splan->indexqualorig =
                    fix_scan_list(root, splan->indexqualorig, rtoffset);
            }
            break;
        case T_BitmapHeapScan:
            {
                BitmapHeapScan *splan = (BitmapHeapScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->bitmapqualorig =
                    fix_scan_list(root, splan->bitmapqualorig, rtoffset);
            }
            break;
        case T_TidScan:
            {
                TidScan    *splan = (TidScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->tidquals =
                    fix_scan_list(root, splan->tidquals, rtoffset);
            }
            break;
        case T_SubqueryScan:
            /* Needs special treatment, see comments below */
            return set_subqueryscan_references(root,
                                               (SubqueryScan *) plan,
                                               rtoffset);
        case T_FunctionScan:
            {
                FunctionScan *splan = (FunctionScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->functions =
                    fix_scan_list(root, splan->functions, rtoffset);
            }
            break;
        case T_TableFuncScan:
            {
                TableFuncScan *splan = (TableFuncScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->tablefunc = (TableFunc *)
                    fix_scan_expr(root, (Node *) splan->tablefunc, rtoffset);
            }
            break;
        case T_ValuesScan:
            {
                ValuesScan *splan = (ValuesScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->values_lists =
                    fix_scan_list(root, splan->values_lists, rtoffset);
            }
            break;
        case T_CteScan:
            {
                CteScan    *splan = (CteScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
            }
            break;
        case T_NamedTuplestoreScan:
            {
                NamedTuplestoreScan *splan = (NamedTuplestoreScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
            }
            break;
        case T_WorkTableScan:
            {
                WorkTableScan *splan = (WorkTableScan *) plan;

                splan->scan.scanrelid += rtoffset;
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
            }
            break;
#ifdef PGXC
        case T_RemoteQuery:
            {
#if 0
                RemoteQuery       *splan = (RemoteQuery *) plan;

                /*
                 * If base_tlist is set, it means that we have a reduced remote
                 * query plan. So need to set the var references accordingly.
                 */
                if (splan->base_tlist)
                    set_remote_references(root, splan, rtoffset);
                splan->scan.plan.targetlist =
                    fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
                splan->scan.plan.qual =
                    fix_scan_list(root, splan->scan.plan.qual, rtoffset);
                splan->base_tlist =
                    fix_scan_list(root, splan->base_tlist, rtoffset);
                splan->scan.scanrelid += rtoffset;
#endif
            }
            break;
#endif
        case T_ForeignScan:
            set_foreignscan_references(root, (ForeignScan *) plan, rtoffset);
            break;
#ifdef XCP
        case T_RemoteSubplan:
            set_remotesubplan_references(root, plan, rtoffset);
            break;
#endif /* XCP */

        case T_CustomScan:
            set_customscan_references(root, (CustomScan *) plan, rtoffset);
            break;

        case T_NestLoop:
        case T_MergeJoin:
        case T_HashJoin:
            set_join_references(root, (Join *) plan, rtoffset);
            break;

        case T_Gather:
        case T_GatherMerge:
            set_upper_references(root, plan, rtoffset);
            break;

        case T_Hash:
        case T_Material:
        case T_Sort:
        case T_Unique:
        case T_SetOp:

            /*
             * These plan types don't actually bother to evaluate their
             * targetlists, because they just return their unmodified input
             * tuples.  Even though the targetlist won't be used by the
             * executor, we fix it up for possible use by EXPLAIN (not to
             * mention ease of debugging --- wrong varnos are very confusing).
             */
            set_dummy_tlist_references(plan, rtoffset);

            /*
             * Since these plan types don't check quals either, we should not
             * find any qual expression attached to them.
             */
            Assert(plan->qual == NIL);
            break;
        case T_LockRows:
            {
                LockRows   *splan = (LockRows *) plan;

                /*
                 * Like the plan types above, LockRows doesn't evaluate its
                 * tlist or quals.  But we have to fix up the RT indexes in
                 * its rowmarks.
                 */
                set_dummy_tlist_references(plan, rtoffset);
                Assert(splan->plan.qual == NIL);

                foreach(l, splan->rowMarks)
                {
                    PlanRowMark *rc = (PlanRowMark *) lfirst(l);

                    rc->rti += rtoffset;
                    rc->prti += rtoffset;
                }
            }
            break;
        case T_Limit:
            {
                Limit       *splan = (Limit *) plan;

                /*
                 * Like the plan types above, Limit doesn't evaluate its tlist
                 * or quals.  It does have live expressions for limit/offset,
                 * however; and those cannot contain subplan variable refs, so
                 * fix_scan_expr works for them.
                 */
                set_dummy_tlist_references(plan, rtoffset);
                Assert(splan->plan.qual == NIL);

                splan->limitOffset =
                    fix_scan_expr(root, splan->limitOffset, rtoffset);
                splan->limitCount =
                    fix_scan_expr(root, splan->limitCount, rtoffset);
            }
            break;
        case T_Agg:
            {
                Agg           *agg = (Agg *) plan;

                /*
                 * If this node is combining partial-aggregation results, we
                 * must convert its Aggrefs to contain references to the
                 * partial-aggregate subexpressions that will be available
                 * from the child plan node.
                 */
                if (DO_AGGSPLIT_COMBINE(agg->aggsplit))
                {
                    plan->targetlist = (List *)
                        convert_combining_aggrefs((Node *) plan->targetlist,
                                                  NULL);
                    plan->qual = (List *)
                        convert_combining_aggrefs((Node *) plan->qual,
                                                  NULL);
                }

                set_upper_references(root, plan, rtoffset);
            }
            break;
        case T_Group:
            set_upper_references(root, plan, rtoffset);
            break;
        case T_WindowAgg:
            {
                WindowAgg  *wplan = (WindowAgg *) plan;

                set_upper_references(root, plan, rtoffset);

                /*
                 * Like Limit node limit/offset expressions, WindowAgg has
                 * frame offset expressions, which cannot contain subplan
                 * variable refs, so fix_scan_expr works for them.
                 */
                wplan->startOffset =
                    fix_scan_expr(root, wplan->startOffset, rtoffset);
                wplan->endOffset =
                    fix_scan_expr(root, wplan->endOffset, rtoffset);
            }
            break;
        case T_Result:
            {
                Result       *splan = (Result *) plan;

                /*
                 * Result may or may not have a subplan; if not, it's more
                 * like a scan node than an upper node.
                 */
                if (splan->plan.lefttree != NULL)
                    set_upper_references(root, plan, rtoffset);
                else
                {
                    splan->plan.targetlist =
                        fix_scan_list(root, splan->plan.targetlist, rtoffset);
                    splan->plan.qual =
                        fix_scan_list(root, splan->plan.qual, rtoffset);
                }
                /* resconstantqual can't contain any subplan variable refs */
                splan->resconstantqual =
                    fix_scan_expr(root, splan->resconstantqual, rtoffset);
            }
            break;
        case T_ProjectSet:
            set_upper_references(root, plan, rtoffset);
            break;
        case T_ModifyTable:
            {
                ModifyTable *splan = (ModifyTable *) plan;

                Assert(splan->plan.targetlist == NIL);
                Assert(splan->plan.qual == NIL);

                splan->withCheckOptionLists =
                    fix_scan_list(root, splan->withCheckOptionLists, rtoffset);

                if (splan->returningLists)
                {
                    List       *newRL = NIL;
                    ListCell   *lcrl,
                               *lcrr,
                               *lcp;

                    /*
                     * Pass each per-subplan returningList through
                     * set_returning_clause_references().
                     */
                    Assert(list_length(splan->returningLists) == list_length(splan->resultRelations));
                    Assert(list_length(splan->returningLists) == list_length(splan->plans));
                    forthree(lcrl, splan->returningLists,
                             lcrr, splan->resultRelations,
                             lcp, splan->plans)
                    {
                        List       *rlist = (List *) lfirst(lcrl);
                        Index        resultrel = lfirst_int(lcrr);
                        Plan       *subplan = (Plan *) lfirst(lcp);

                        rlist = set_returning_clause_references(root,
                                                                rlist,
                                                                subplan,
                                                                resultrel,
                                                                rtoffset);
                        newRL = lappend(newRL, rlist);
                    }
                    splan->returningLists = newRL;

                    /*
                     * Set up the visible plan targetlist as being the same as
                     * the first RETURNING list. This is for the use of
                     * EXPLAIN; the executor won't pay any attention to the
                     * targetlist.  We postpone this step until here so that
                     * we don't have to do set_returning_clause_references()
                     * twice on identical targetlists.
                     */
                    splan->plan.targetlist = copyObject(linitial(newRL));
                }

                /*
                 * We treat ModifyTable with ON CONFLICT as a form of 'pseudo
                 * join', where the inner side is the EXCLUDED tuple.
                 * Therefore use fix_join_expr to setup the relevant variables
                 * to INNER_VAR. We explicitly don't create any OUTER_VARs as
                 * those are already used by RETURNING and it seems better to
                 * be non-conflicting.
                 */
                if (splan->onConflictSet)
                {
                    indexed_tlist *itlist;

                    itlist = build_tlist_index(splan->exclRelTlist);

                    splan->onConflictSet =
                        fix_join_expr(root, splan->onConflictSet,
                                      NULL, itlist,
                                      linitial_int(splan->resultRelations),
                                      rtoffset);

                    splan->onConflictWhere = (Node *)
                        fix_join_expr(root, (List *) splan->onConflictWhere,
                                      NULL, itlist,
                                      linitial_int(splan->resultRelations),
                                      rtoffset);

                    pfree(itlist);

                    splan->exclRelTlist =
                        fix_scan_list(root, splan->exclRelTlist, rtoffset);
                }

                splan->nominalRelation += rtoffset;
                splan->exclRelRTI += rtoffset;

                foreach(l, splan->partitioned_rels)
                {
                    lfirst_int(l) += rtoffset;
                }
                foreach(l, splan->resultRelations)
                {
                    lfirst_int(l) += rtoffset;
                }
                foreach(l, splan->rowMarks)
                {
                    PlanRowMark *rc = (PlanRowMark *) lfirst(l);

                    rc->rti += rtoffset;
                    rc->prti += rtoffset;
                }
                foreach(l, splan->plans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
#ifdef __TBASE__
                foreach(l, splan->partplans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
#endif
                /*
                 * Append this ModifyTable node's final result relation RT
                 * index(es) to the global list for the plan, and set its
                 * resultRelIndex to reflect their starting position in the
                 * global list.
                 */
                splan->resultRelIndex = list_length(root->glob->resultRelations);
                root->glob->resultRelations =
                    list_concat(root->glob->resultRelations,
                                list_copy(splan->resultRelations));

                /*
                 * If the main target relation is a partitioned table, the
                 * following list contains the RT indexes of partitioned child
                 * relations including the root, which are not included in the
                 * above list.  We also keep RT indexes of the roots
                 * separately to be identitied as such during the executor
                 * initialization.
                 */
                if (splan->partitioned_rels != NIL)
                {
                    root->glob->nonleafResultRelations =
                        list_concat(root->glob->nonleafResultRelations,
                                    list_copy(splan->partitioned_rels));
                    /* Remember where this root will be in the global list. */
                    splan->rootResultRelIndex =
                        list_length(root->glob->rootResultRelations);
                    root->glob->rootResultRelations =
                        lappend_int(root->glob->rootResultRelations,
                                    linitial_int(splan->partitioned_rels));
                }
            }
            break;
        case T_Append:
            {
                Append       *splan = (Append *) plan;

                /*
                 * Append, like Sort et al, doesn't actually evaluate its
                 * targetlist or check quals.
                 */
                set_dummy_tlist_references(plan, rtoffset);
                Assert(splan->plan.qual == NIL);
                foreach(l, splan->partitioned_rels)
                {
                    lfirst_int(l) += rtoffset;
                }
                foreach(l, splan->appendplans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
            }
            break;
        case T_MergeAppend:
            {
                MergeAppend *splan = (MergeAppend *) plan;

                /*
                 * MergeAppend, like Sort et al, doesn't actually evaluate its
                 * targetlist or check quals.
                 */
                set_dummy_tlist_references(plan, rtoffset);
                Assert(splan->plan.qual == NIL);
                foreach(l, splan->partitioned_rels)
                {
                    lfirst_int(l) += rtoffset;
                }
                foreach(l, splan->mergeplans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
            }
            break;
        case T_RecursiveUnion:
            /* This doesn't evaluate targetlist or check quals either */
            set_dummy_tlist_references(plan, rtoffset);
            Assert(plan->qual == NIL);
            break;
        case T_BitmapAnd:
            {
                BitmapAnd  *splan = (BitmapAnd *) plan;

                /* BitmapAnd works like Append, but has no tlist */
                Assert(splan->plan.targetlist == NIL);
                Assert(splan->plan.qual == NIL);
                foreach(l, splan->bitmapplans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
            }
            break;
        case T_BitmapOr:
            {
                BitmapOr   *splan = (BitmapOr *) plan;

                /* BitmapOr works like Append, but has no tlist */
                Assert(splan->plan.targetlist == NIL);
                Assert(splan->plan.qual == NIL);
                foreach(l, splan->bitmapplans)
                {
                    lfirst(l) = set_plan_refs(root,
                                              (Plan *) lfirst(l),
                                              rtoffset);
                }
            }
            break;
        default:
            elog(ERROR, "unrecognized node type: %d",
                 (int) nodeTag(plan));
            break;
    }

    /*
     * Now recurse into child plans, if any
     *
     * NOTE: it is essential that we recurse into child plans AFTER we set
     * subplan references in this plan's tlist and quals.  If we did the
     * reference-adjustments bottom-up, then we would fail to match this
     * plan's var nodes against the already-modified nodes of the children.
     */
    plan->lefttree = set_plan_refs(root, plan->lefttree, rtoffset);
    plan->righttree = set_plan_refs(root, plan->righttree, rtoffset);

    return plan;
}

/*
 * set_indexonlyscan_references
 *        Do set_plan_references processing on an IndexOnlyScan
 *
 * This is unlike the handling of a plain IndexScan because we have to
 * convert Vars referencing the heap into Vars referencing the index.
 * We can use the fix_upper_expr machinery for that, by working from a
 * targetlist describing the index columns.
 */
static Plan *
set_indexonlyscan_references(PlannerInfo *root,
                             IndexOnlyScan *plan,
                             int rtoffset)
{
    indexed_tlist *index_itlist;

    index_itlist = build_tlist_index(plan->indextlist);

    plan->scan.scanrelid += rtoffset;

    plan->scan.plan.targetlist = (List *)
        fix_upper_expr(root,
                       (Node *) plan->scan.plan.targetlist,
                       index_itlist,
                       INDEX_VAR,
                       rtoffset);
    plan->scan.plan.qual = (List *)
        fix_upper_expr(root,
                       (Node *) plan->scan.plan.qual,
                       index_itlist,
                       INDEX_VAR,
                       rtoffset);

    /* indexqual is already transformed to reference index columns */
    plan->indexqual = fix_scan_list(root, plan->indexqual, rtoffset);
    /* indexorderby is already transformed to reference index columns */
    plan->indexorderby = fix_scan_list(root, plan->indexorderby, rtoffset);
    /* indextlist must NOT be transformed to reference index columns */
    plan->indextlist = fix_scan_list(root, plan->indextlist, rtoffset);

    pfree(index_itlist);

    return (Plan *) plan;
}

/*
 * set_subqueryscan_references
 *        Do set_plan_references processing on a SubqueryScan
 *
 * We try to strip out the SubqueryScan entirely; if we can't, we have
 * to do the normal processing on it.
 */
static Plan *
set_subqueryscan_references(PlannerInfo *root,
                            SubqueryScan *plan,
                            int rtoffset)
{
    RelOptInfo *rel;
    Plan       *result;

    /* Need to look up the subquery's RelOptInfo, since we need its subroot */
    rel = find_base_rel(root, plan->scan.scanrelid);

    /* Recursively process the subplan */
    plan->subplan = set_plan_references(rel->subroot, plan->subplan);

    if (trivial_subqueryscan(plan))
    {
        /*
         * We can omit the SubqueryScan node and just pull up the subplan.
         */
        ListCell   *lp,
                   *lc;

        result = plan->subplan;

        /* We have to be sure we don't lose any initplans */
        result->initPlan = list_concat(plan->scan.plan.initPlan,
                                       result->initPlan);

        /*
         * We also have to transfer the SubqueryScan's result-column names
         * into the subplan, else columns sent to client will be improperly
         * labeled if this is the topmost plan level.  Copy the "source
         * column" information too.
         */
        forboth(lp, plan->scan.plan.targetlist, lc, result->targetlist)
        {
            TargetEntry *ptle = (TargetEntry *) lfirst(lp);
            TargetEntry *ctle = (TargetEntry *) lfirst(lc);

            ctle->resname = ptle->resname;
            ctle->resorigtbl = ptle->resorigtbl;
            ctle->resorigcol = ptle->resorigcol;
        }
    }
    else
    {
        /*
         * Keep the SubqueryScan node.  We have to do the processing that
         * set_plan_references would otherwise have done on it.  Notice we do
         * not do set_upper_references() here, because a SubqueryScan will
         * always have been created with correct references to its subplan's
         * outputs to begin with.
         */
        plan->scan.scanrelid += rtoffset;
        plan->scan.plan.targetlist =
            fix_scan_list(root, plan->scan.plan.targetlist, rtoffset);
        plan->scan.plan.qual =
            fix_scan_list(root, plan->scan.plan.qual, rtoffset);

        result = (Plan *) plan;
    }

    return result;
}

/*
 * trivial_subqueryscan
 *        Detect whether a SubqueryScan can be deleted from the plan tree.
 *
 * We can delete it if it has no qual to check and the targetlist just
 * regurgitates the output of the child plan.
 */
static bool
trivial_subqueryscan(SubqueryScan *plan)
{// #lizard forgives
    int            attrno;
    ListCell   *lp,
               *lc;

    if (plan->scan.plan.qual != NIL)
        return false;

    if (list_length(plan->scan.plan.targetlist) !=
        list_length(plan->subplan->targetlist))
        return false;            /* tlists not same length */

    attrno = 1;
    forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
    {
        TargetEntry *ptle = (TargetEntry *) lfirst(lp);
        TargetEntry *ctle = (TargetEntry *) lfirst(lc);

        if (ptle->resjunk != ctle->resjunk)
            return false;        /* tlist doesn't match junk status */

        /*
         * We accept either a Var referencing the corresponding element of the
         * subplan tlist, or a Const equaling the subplan element. See
         * generate_setop_tlist() for motivation.
         */
        if (ptle->expr && IsA(ptle->expr, Var))
        {
            Var           *var = (Var *) ptle->expr;

            Assert(var->varno == plan->scan.scanrelid);
            Assert(var->varlevelsup == 0);
            if (var->varattno != attrno)
                return false;    /* out of order */
        }
        else if (ptle->expr && IsA(ptle->expr, Const))
        {
            if (!equal(ptle->expr, ctle->expr))
                return false;
        }
        else
            return false;

        attrno++;
    }

    return true;
}

/*
 * set_foreignscan_references
 *       Do set_plan_references processing on a ForeignScan
 */
static void
set_foreignscan_references(PlannerInfo *root,
                           ForeignScan *fscan,
                           int rtoffset)
{
    /* Adjust scanrelid if it's valid */
    if (fscan->scan.scanrelid > 0)
        fscan->scan.scanrelid += rtoffset;

    if (fscan->fdw_scan_tlist != NIL || fscan->scan.scanrelid == 0)
    {
        /*
         * Adjust tlist, qual, fdw_exprs, fdw_recheck_quals to reference
         * foreign scan tuple
         */
        indexed_tlist *itlist = build_tlist_index(fscan->fdw_scan_tlist);

        fscan->scan.plan.targetlist = (List *)
            fix_upper_expr(root,
                           (Node *) fscan->scan.plan.targetlist,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        fscan->scan.plan.qual = (List *)
            fix_upper_expr(root,
                           (Node *) fscan->scan.plan.qual,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        fscan->fdw_exprs = (List *)
            fix_upper_expr(root,
                           (Node *) fscan->fdw_exprs,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        fscan->fdw_recheck_quals = (List *)
            fix_upper_expr(root,
                           (Node *) fscan->fdw_recheck_quals,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        pfree(itlist);
        /* fdw_scan_tlist itself just needs fix_scan_list() adjustments */
        fscan->fdw_scan_tlist =
            fix_scan_list(root, fscan->fdw_scan_tlist, rtoffset);
    }
    else
    {
        /*
         * Adjust tlist, qual, fdw_exprs, fdw_recheck_quals in the standard
         * way
         */
        fscan->scan.plan.targetlist =
            fix_scan_list(root, fscan->scan.plan.targetlist, rtoffset);
        fscan->scan.plan.qual =
            fix_scan_list(root, fscan->scan.plan.qual, rtoffset);
        fscan->fdw_exprs =
            fix_scan_list(root, fscan->fdw_exprs, rtoffset);
        fscan->fdw_recheck_quals =
            fix_scan_list(root, fscan->fdw_recheck_quals, rtoffset);
    }

    /* Adjust fs_relids if needed */
    if (rtoffset > 0)
    {
        Bitmapset  *tempset = NULL;
        int            x = -1;

        while ((x = bms_next_member(fscan->fs_relids, x)) >= 0)
            tempset = bms_add_member(tempset, x + rtoffset);
        fscan->fs_relids = tempset;
    }
}

/*
 * set_customscan_references
 *       Do set_plan_references processing on a CustomScan
 */
static void
set_customscan_references(PlannerInfo *root,
                          CustomScan *cscan,
                          int rtoffset)
{
    ListCell   *lc;

    /* Adjust scanrelid if it's valid */
    if (cscan->scan.scanrelid > 0)
        cscan->scan.scanrelid += rtoffset;

    if (cscan->custom_scan_tlist != NIL || cscan->scan.scanrelid == 0)
    {
        /* Adjust tlist, qual, custom_exprs to reference custom scan tuple */
        indexed_tlist *itlist = build_tlist_index(cscan->custom_scan_tlist);

        cscan->scan.plan.targetlist = (List *)
            fix_upper_expr(root,
                           (Node *) cscan->scan.plan.targetlist,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        cscan->scan.plan.qual = (List *)
            fix_upper_expr(root,
                           (Node *) cscan->scan.plan.qual,
                           itlist,
                           INDEX_VAR,
                           rtoffset);
        cscan->custom_exprs = (List *)
            fix_upper_expr(root,
                           (Node *) cscan->custom_exprs,
                           itlist,
                           INDEX_VAR,
                           rtoffset);

        pfree(itlist);
        /* custom_scan_tlist itself just needs fix_scan_list() adjustments */
        cscan->custom_scan_tlist =
            fix_scan_list(root, cscan->custom_scan_tlist, rtoffset);
    }
    else
    {
        /* Adjust tlist, qual, custom_exprs in the standard way */
        cscan->scan.plan.targetlist =
            fix_scan_list(root, cscan->scan.plan.targetlist, rtoffset);
        cscan->scan.plan.qual =
            fix_scan_list(root, cscan->scan.plan.qual, rtoffset);
        cscan->custom_exprs =
            fix_scan_list(root, cscan->custom_exprs, rtoffset);
    }

    /* Adjust child plan-nodes recursively, if needed */
    foreach(lc, cscan->custom_plans)
    {
        lfirst(lc) = set_plan_refs(root, (Plan *) lfirst(lc), rtoffset);
    }

    /* Adjust custom_relids if needed */
    if (rtoffset > 0)
    {
        Bitmapset  *tempset = NULL;
        int            x = -1;

        while ((x = bms_next_member(cscan->custom_relids, x)) >= 0)
            tempset = bms_add_member(tempset, x + rtoffset);
        cscan->custom_relids = tempset;
    }
}

/*
 * copyVar
 *        Copy a Var node.
 *
 * fix_scan_expr and friends do this enough times that it's worth having
 * a bespoke routine instead of using the generic copyObject() function.
 */
static inline Var *
copyVar(Var *var)
{
    Var           *newvar = (Var *) palloc(sizeof(Var));

    *newvar = *var;
    return newvar;
}

/*
 * fix_expr_common
 *        Do generic set_plan_references processing on an expression node
 *
 * This is code that is common to all variants of expression-fixing.
 * We must look up operator opcode info for OpExpr and related nodes,
 * add OIDs from regclass Const nodes into root->glob->relationOids, and
 * add PlanInvalItems for user-defined functions into root->glob->invalItems.
 * We also fill in column index lists for GROUPING() expressions.
 *
 * We assume it's okay to update opcode info in-place.  So this could possibly
 * scribble on the planner's input data structures, but it's OK.
 */
static void
fix_expr_common(PlannerInfo *root, Node *node)
{// #lizard forgives
    /* We assume callers won't call us on a NULL pointer */
    if (IsA(node, Aggref))
    {
        record_plan_function_dependency(root,
                                        ((Aggref *) node)->aggfnoid);
    }
    else if (IsA(node, WindowFunc))
    {
        record_plan_function_dependency(root,
                                        ((WindowFunc *) node)->winfnoid);
    }
    else if (IsA(node, FuncExpr))
    {
        record_plan_function_dependency(root,
                                        ((FuncExpr *) node)->funcid);
    }
    else if (IsA(node, OpExpr))
    {
        set_opfuncid((OpExpr *) node);
        record_plan_function_dependency(root,
                                        ((OpExpr *) node)->opfuncid);
    }
    else if (IsA(node, DistinctExpr))
    {
        set_opfuncid((OpExpr *) node);    /* rely on struct equivalence */
        record_plan_function_dependency(root,
                                        ((DistinctExpr *) node)->opfuncid);
    }
    else if (IsA(node, NullIfExpr))
    {
        set_opfuncid((OpExpr *) node);    /* rely on struct equivalence */
        record_plan_function_dependency(root,
                                        ((NullIfExpr *) node)->opfuncid);
    }
    else if (IsA(node, ScalarArrayOpExpr))
    {
        set_sa_opfuncid((ScalarArrayOpExpr *) node);
        record_plan_function_dependency(root,
                                        ((ScalarArrayOpExpr *) node)->opfuncid);
    }
    else if (IsA(node, ArrayCoerceExpr))
    {
        if (OidIsValid(((ArrayCoerceExpr *) node)->elemfuncid))
            record_plan_function_dependency(root,
                                            ((ArrayCoerceExpr *) node)->elemfuncid);
    }
    else if (IsA(node, Const))
    {
        Const       *con = (Const *) node;

        /* Check for regclass reference */
        if (ISREGCLASSCONST(con))
            root->glob->relationOids =
                lappend_oid(root->glob->relationOids,
                            DatumGetObjectId(con->constvalue));
    }
    else if (IsA(node, GroupingFunc))
    {
        GroupingFunc *g = (GroupingFunc *) node;
        AttrNumber *grouping_map = root->grouping_map;

        /* If there are no grouping sets, we don't need this. */

        Assert(grouping_map || g->cols == NIL);

        if (grouping_map)
        {
            ListCell   *lc;
            List       *cols = NIL;

            foreach(lc, g->refs)
            {
                cols = lappend_int(cols, grouping_map[lfirst_int(lc)]);
            }

            Assert(!g->cols || equal(cols, g->cols));

            if (!g->cols)
                g->cols = cols;
        }
    }
}

/*
 * fix_param_node
 *        Do set_plan_references processing on a Param
 *
 * If it's a PARAM_MULTIEXPR, replace it with the appropriate Param from
 * root->multiexpr_params; otherwise no change is needed.
 * Just for paranoia's sake, we make a copy of the node in either case.
 */
static Node *
fix_param_node(PlannerInfo *root, Param *p)
{
    if (p->paramkind == PARAM_MULTIEXPR)
    {
        int            subqueryid = p->paramid >> 16;
        int            colno = p->paramid & 0xFFFF;
        List       *params;

        if (subqueryid <= 0 ||
            subqueryid > list_length(root->multiexpr_params))
            elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
        params = (List *) list_nth(root->multiexpr_params, subqueryid - 1);
        if (colno <= 0 || colno > list_length(params))
            elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
        return copyObject(list_nth(params, colno - 1));
    }
    return (Node *) copyObject(p);
}

/*
 * fix_scan_expr
 *        Do set_plan_references processing on a scan-level expression
 *
 * This consists of incrementing all Vars' varnos by rtoffset,
 * replacing PARAM_MULTIEXPR Params, expanding PlaceHolderVars,
 * replacing Aggref nodes that should be replaced by initplan output Params,
 * looking up operator opcode info for OpExpr and related nodes,
 * and adding OIDs from regclass Const nodes into root->glob->relationOids.
 */
static Node *
fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset)
{
    fix_scan_expr_context context;

    context.root = root;
    context.rtoffset = rtoffset;

    if (rtoffset != 0 ||
        root->multiexpr_params != NIL ||
        root->glob->lastPHId != 0 ||
        root->minmax_aggs != NIL)
    {
        return fix_scan_expr_mutator(node, &context);
    }
    else
    {
        /*
         * If rtoffset == 0, we don't need to change any Vars, and if there
         * are no MULTIEXPR subqueries then we don't need to replace
         * PARAM_MULTIEXPR Params, and if there are no placeholders anywhere
         * we won't need to remove them, and if there are no minmax Aggrefs we
         * won't need to replace them.  Then it's OK to just scribble on the
         * input node tree instead of copying (since the only change, filling
         * in any unset opfuncid fields, is harmless).  This saves just enough
         * cycles to be noticeable on trivial queries.
         */
        (void) fix_scan_expr_walker(node, &context);
        return node;
    }
}

static Node *
fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
{// #lizard forgives
    if (node == NULL)
        return NULL;
    if (IsA(node, Var))
    {
        Var           *var = copyVar((Var *) node);

        Assert(var->varlevelsup == 0);

        /*
         * We should not see any Vars marked INNER_VAR or OUTER_VAR.  But an
         * indexqual expression could contain INDEX_VAR Vars.
         */
        Assert(var->varno != INNER_VAR);
        Assert(var->varno != OUTER_VAR);
        if (!IS_SPECIAL_VARNO(var->varno))
            var->varno += context->rtoffset;
        if (var->varnoold > 0)
            var->varnoold += context->rtoffset;
        return (Node *) var;
    }
    if (IsA(node, Param))
        return fix_param_node(context->root, (Param *) node);
    if (IsA(node, Aggref))
    {
        Aggref       *aggref = (Aggref *) node;

        /* See if the Aggref should be replaced by a Param */
        if (context->root->minmax_aggs != NIL &&
            list_length(aggref->args) == 1)
        {
            TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
            ListCell   *lc;

            foreach(lc, context->root->minmax_aggs)
            {
                MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);

                if (mminfo->aggfnoid == aggref->aggfnoid &&
                    equal(mminfo->target, curTarget->expr))
                    return (Node *) copyObject(mminfo->param);
            }
        }
        /* If no match, just fall through to process it normally */
    }
    if (IsA(node, CurrentOfExpr))
    {
        CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);

        Assert(cexpr->cvarno != INNER_VAR);
        Assert(cexpr->cvarno != OUTER_VAR);
        if (!IS_SPECIAL_VARNO(cexpr->cvarno))
            cexpr->cvarno += context->rtoffset;
        return (Node *) cexpr;
    }
    if (IsA(node, PlaceHolderVar))
    {
        /* At scan level, we should always just evaluate the contained expr */
        PlaceHolderVar *phv = (PlaceHolderVar *) node;

        return fix_scan_expr_mutator((Node *) phv->phexpr, context);
    }
    fix_expr_common(context->root, node);
    return expression_tree_mutator(node, fix_scan_expr_mutator,
                                   (void *) context);
}

static bool
fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
{
    if (node == NULL)
        return false;
    Assert(!IsA(node, PlaceHolderVar));
    fix_expr_common(context->root, node);
    return expression_tree_walker(node, fix_scan_expr_walker,
                                  (void *) context);
}

/*
 * set_join_references
 *      Modify the target list and quals of a join node to reference its
 *      subplans, by setting the varnos to OUTER_VAR or INNER_VAR and setting
 *      attno values to the result domain number of either the corresponding
 *      outer or inner join tuple item.  Also perform opcode lookup for these
 *      expressions, and add regclass OIDs to root->glob->relationOids.
 */
static void
set_join_references(PlannerInfo *root, Join *join, int rtoffset)
{
	Plan	   *outer_plan = join->plan.lefttree;
	Plan	   *inner_plan = join->plan.righttree;
	indexed_tlist *outer_itlist;
	indexed_tlist *inner_itlist;

	outer_itlist = build_tlist_index(outer_plan->targetlist);
	inner_itlist = build_tlist_index(inner_plan->targetlist);

	/*
	 * First process the joinquals (including merge or hash clauses).  These
	 * are logically below the join so they can always use all values
	 * available from the input tlists.  It's okay to also handle
	 * NestLoopParams now, because those couldn't refer to nullable
	 * subexpressions.
	 */
	join->joinqual = fix_join_expr(root,
								   join->joinqual,
								   outer_itlist,
								   inner_itlist,
								   (Index) 0,
								   rtoffset);

	/* Now do join-type-specific stuff */
	if (IsA(join, NestLoop))
	{
		NestLoop   *nl = (NestLoop *) join;
		ListCell   *lc;

		foreach(lc, nl->nestParams)
		{
			NestLoopParam *nlp = (NestLoopParam *) lfirst(lc);

			nlp->paramval = (Var *) fix_upper_expr(root,
												   (Node *) nlp->paramval,
												   outer_itlist,
												   OUTER_VAR,
												   rtoffset);

			/* Check we replaced any PlaceHolderVar with simple Var */
			if (!(IsA(nlp->paramval, Var) &&
				  nlp->paramval->varno == OUTER_VAR))
				elog(ERROR, "NestLoopParam was not reduced to a simple Var");
		}
	}
	else if (IsA(join, MergeJoin))
	{
		MergeJoin  *mj = (MergeJoin *) join;

		mj->mergeclauses = fix_join_expr(root,
										 mj->mergeclauses,
										 outer_itlist,
										 inner_itlist,
										 (Index) 0,
										 rtoffset);
	}
	else if (IsA(join, HashJoin))
	{
		HashJoin   *hj = (HashJoin *) join;

		hj->hashclauses = fix_join_expr(root,
										hj->hashclauses,
										outer_itlist,
										inner_itlist,
										(Index) 0,
										rtoffset);
	}

	/*
	 * Now we need to fix up the targetlist and qpqual, which are logically
	 * above the join.  This means they should not re-use any input expression
	 * that was computed in the nullable side of an outer join.  Vars and
	 * PlaceHolderVars are fine, so we can implement this restriction just by
	 * clearing has_non_vars in the indexed_tlist structs.
	 *
	 * XXX This is a grotty workaround for the fact that we don't clearly
	 * distinguish between a Var appearing below an outer join and the "same"
	 * Var appearing above it.  If we did, we'd not need to hack the matching
	 * rules this way.
	 */
	switch (join->jointype)
	{
		case JOIN_LEFT:
		case JOIN_SEMI:
		case JOIN_ANTI:
#ifdef __TBASE__
        case JOIN_LEFT_SCALAR:
        case JOIN_LEFT_SEMI:
#endif
			inner_itlist->has_non_vars = false;
			break;
		case JOIN_RIGHT:
			outer_itlist->has_non_vars = false;
			break;
		case JOIN_FULL:
			outer_itlist->has_non_vars = false;
			inner_itlist->has_non_vars = false;
			break;
		default:
			break;
	}

	join->plan.targetlist = fix_join_expr(root,
										  join->plan.targetlist,
										  outer_itlist,
										  inner_itlist,
										  (Index) 0,
										  rtoffset);
	join->plan.qual = fix_join_expr(root,
									join->plan.qual,
									outer_itlist,
									inner_itlist,
									(Index) 0,
									rtoffset);

	pfree(outer_itlist);
	pfree(inner_itlist);
}

/*
 * set_upper_references
 *      Update the targetlist and quals of an upper-level plan node
 *      to refer to the tuples returned by its lefttree subplan.
 *      Also perform opcode lookup for these expressions, and
 *      add regclass OIDs to root->glob->relationOids.
 *
 * This is used for single-input plan types like Agg, Group, Result.
 *
 * In most cases, we have to match up individual Vars in the tlist and
 * qual expressions with elements of the subplan's tlist (which was
 * generated by flattening these selfsame expressions, so it should have all
 * the required variables).  There is an important exception, however:
 * depending on where we are in the plan tree, sort/group columns may have
 * been pushed into the subplan tlist unflattened.  If these values are also
 * needed in the output then we want to reference the subplan tlist element
 * rather than recomputing the expression.
 */
static void
set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset)
{
    Plan       *subplan = plan->lefttree;
    indexed_tlist *subplan_itlist;
    List       *output_targetlist;
    ListCell   *l;

    subplan_itlist = build_tlist_index(subplan->targetlist);

    output_targetlist = NIL;
    foreach(l, plan->targetlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(l);
        Node       *newexpr;

        /* If it's a non-Var sort/group item, first try to match by sortref */
        if (tle->ressortgroupref != 0 && !IsA(tle->expr, Var))
        {
            newexpr = (Node *)
                search_indexed_tlist_for_sortgroupref(tle->expr,
                                                      tle->ressortgroupref,
                                                      subplan_itlist,
                                                      OUTER_VAR);
            if (!newexpr)
                newexpr = fix_upper_expr(root,
                                         (Node *) tle->expr,
                                         subplan_itlist,
                                         OUTER_VAR,
                                         rtoffset);
        }
        else
            newexpr = fix_upper_expr(root,
                                     (Node *) tle->expr,
                                     subplan_itlist,
                                     OUTER_VAR,
                                     rtoffset);

        tle = flatCopyTargetEntry(tle);
        tle->expr = (Expr *) newexpr;
        output_targetlist = lappend(output_targetlist, tle);
    }
    plan->targetlist = output_targetlist;

    plan->qual = (List *)
        fix_upper_expr(root,
                       (Node *) plan->qual,
                       subplan_itlist,
                       OUTER_VAR,
                       rtoffset);
    pfree(subplan_itlist);
}

/*
 * Recursively scan an expression tree and convert Aggrefs to the proper
 * intermediate form for combining aggregates.  This means (1) replacing each
 * one's argument list with a single argument that is the original Aggref
 * modified to show partial aggregation and (2) changing the upper Aggref to
 * show combining aggregation.
 *
 * After this step, set_upper_references will replace the partial Aggrefs
 * with Vars referencing the lower Agg plan node's outputs, so that the final
 * form seen by the executor is a combining Aggref with a Var as input.
 *
 * It's rather messy to postpone this step until setrefs.c; ideally it'd be
 * done in createplan.c.  The difficulty is that once we modify the Aggref
 * expressions, they will no longer be equal() to their original form and
 * so cross-plan-node-level matches will fail.  So this has to happen after
 * the plan node above the Agg has resolved its subplan references.
 */
static Node *
convert_combining_aggrefs(Node *node, void *context)
{
    if (node == NULL)
        return NULL;
    if (IsA(node, Aggref))
    {
        Aggref       *orig_agg = (Aggref *) node;
        Aggref       *child_agg;
        Aggref       *parent_agg;

        /* Assert we've not chosen to partial-ize any unsupported cases */
        Assert(orig_agg->aggorder == NIL);

        /*
         * Since aggregate calls can't be nested, we needn't recurse into the
         * arguments.  But for safety, flat-copy the Aggref node itself rather
         * than modifying it in-place.
         */
        child_agg = makeNode(Aggref);
        memcpy(child_agg, orig_agg, sizeof(Aggref));

        /*
         * For the parent Aggref, we want to copy all the fields of the
         * original aggregate *except* the args list, which we'll replace
         * below, and the aggfilter expression, which should be applied only
         * by the child not the parent.  Rather than explicitly knowing about
         * all the other fields here, we can momentarily modify child_agg to
         * provide a suitable source for copyObject.
         */
        child_agg->args = NIL;
        child_agg->aggfilter = NULL;
        parent_agg = copyObject(child_agg);
        child_agg->args = orig_agg->args;
        child_agg->aggfilter = orig_agg->aggfilter;

        /*
         * Now, set up child_agg to represent the first phase of partial
         * aggregation.  For now, assume serialization is required.
         */
        mark_partial_aggref(child_agg, AGGSPLIT_INITIAL_SERIAL);

        /*
         * And set up parent_agg to represent the second phase.
         */
        parent_agg->args = list_make1(makeTargetEntry((Expr *) child_agg,
                                                      1, NULL, false));
        mark_partial_aggref(parent_agg, AGGSPLIT_FINAL_DESERIAL);

        return (Node *) parent_agg;
    }
    return expression_tree_mutator(node, convert_combining_aggrefs,
                                   (void *) context);
}

/*
 * set_dummy_tlist_references
 *      Replace the targetlist of an upper-level plan node with a simple
 *      list of OUTER_VAR references to its child.
 *
 * This is used for plan types like Sort and Append that don't evaluate
 * their targetlists.  Although the executor doesn't care at all what's in
 * the tlist, EXPLAIN needs it to be realistic.
 *
 * Note: we could almost use set_upper_references() here, but it fails for
 * Append for lack of a lefttree subplan.  Single-purpose code is faster
 * anyway.
 */
static void
set_dummy_tlist_references(Plan *plan, int rtoffset)
{
    List       *output_targetlist;
    ListCell   *l;

    output_targetlist = NIL;
    foreach(l, plan->targetlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(l);
        Var           *oldvar = (Var *) tle->expr;
        Var           *newvar;

        /*
         * As in search_indexed_tlist_for_non_var(), we prefer to keep Consts
         * as Consts, not Vars referencing Consts.  Here, there's no speed
         * advantage to be had, but it makes EXPLAIN output look cleaner, and
         * again it avoids confusing the executor.
         */
        if (IsA(oldvar, Const))
        {
            /* just reuse the existing TLE node */
            output_targetlist = lappend(output_targetlist, tle);
            continue;
        }

        newvar = makeVar(OUTER_VAR,
                         tle->resno,
                         exprType((Node *) oldvar),
                         exprTypmod((Node *) oldvar),
                         exprCollation((Node *) oldvar),
                         0);
        if (IsA(oldvar, Var))
        {
            newvar->varnoold = oldvar->varno + rtoffset;
            newvar->varoattno = oldvar->varattno;
        }
        else
        {
            newvar->varnoold = 0;    /* wasn't ever a plain Var */
            newvar->varoattno = 0;
        }

        tle = flatCopyTargetEntry(tle);
        tle->expr = (Expr *) newvar;
        output_targetlist = lappend(output_targetlist, tle);
    }
    plan->targetlist = output_targetlist;

    /* We don't touch plan->qual here */
}


/*
 * build_tlist_index --- build an index data structure for a child tlist
 *
 * In most cases, subplan tlists will be "flat" tlists with only Vars,
 * so we try to optimize that case by extracting information about Vars
 * in advance.  Matching a parent tlist to a child is still an O(N^2)
 * operation, but at least with a much smaller constant factor than plain
 * tlist_member() searches.
 *
 * The result of this function is an indexed_tlist struct to pass to
 * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
 * When done, the indexed_tlist may be freed with a single pfree().
 */
static indexed_tlist *
build_tlist_index(List *tlist)
{
    indexed_tlist *itlist;
    tlist_vinfo *vinfo;
    ListCell   *l;

    /* Create data structure with enough slots for all tlist entries */
    itlist = (indexed_tlist *)
        palloc(offsetof(indexed_tlist, vars) +
               list_length(tlist) * sizeof(tlist_vinfo));

    itlist->tlist = tlist;
    itlist->has_ph_vars = false;
    itlist->has_non_vars = false;
	itlist->has_conv_whole_rows = false;

    /* Find the Vars and fill in the index array */
    vinfo = itlist->vars;
    foreach(l, tlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(l);

        if (tle->expr && IsA(tle->expr, Var))
        {
            Var           *var = (Var *) tle->expr;

            vinfo->varno = var->varno;
            vinfo->varattno = var->varattno;
            vinfo->resno = tle->resno;
            vinfo++;
        }
        else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
            itlist->has_ph_vars = true;
		else if (is_converted_whole_row_reference((Node *) tle->expr))
			itlist->has_conv_whole_rows = true;
        else
            itlist->has_non_vars = true;
    }

    itlist->num_vars = (vinfo - itlist->vars);

    return itlist;
}

/*
 * build_tlist_index_other_vars --- build a restricted tlist index
 *
 * This is like build_tlist_index, but we only index tlist entries that
 * are Vars belonging to some rel other than the one specified.  We will set
 * has_ph_vars (allowing PlaceHolderVars to be matched), but not has_non_vars
 * (so nothing other than Vars and PlaceHolderVars can be matched). In case of
 * DML, where this function will be used, returning lists from child relations
 * will be appended similar to a simple append relation. That does not require
 * fixing ConvertRowtypeExpr references. So, those are not considered here.
 */
static indexed_tlist *
build_tlist_index_other_vars(List *tlist, Index ignore_rel)
{
    indexed_tlist *itlist;
    tlist_vinfo *vinfo;
    ListCell   *l;

    /* Create data structure with enough slots for all tlist entries */
    itlist = (indexed_tlist *)
        palloc(offsetof(indexed_tlist, vars) +
               list_length(tlist) * sizeof(tlist_vinfo));

    itlist->tlist = tlist;
    itlist->has_ph_vars = false;
    itlist->has_non_vars = false;
	itlist->has_conv_whole_rows = false;

    /* Find the desired Vars and fill in the index array */
    vinfo = itlist->vars;
    foreach(l, tlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(l);

        if (tle->expr && IsA(tle->expr, Var))
        {
            Var           *var = (Var *) tle->expr;

            if (var->varno != ignore_rel)
            {
                vinfo->varno = var->varno;
                vinfo->varattno = var->varattno;
                vinfo->resno = tle->resno;
                vinfo++;
            }
        }
        else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
            itlist->has_ph_vars = true;
    }

    itlist->num_vars = (vinfo - itlist->vars);

    return itlist;
}

/*
 * search_indexed_tlist_for_var --- find a Var in an indexed tlist
 *
 * If a match is found, return a copy of the given Var with suitably
 * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
 * Also ensure that varnoold is incremented by rtoffset.
 * If no match, return NULL.
 */
static Var *
search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
                             Index newvarno, int rtoffset)
{
    Index        varno = var->varno;
    AttrNumber    varattno = var->varattno;
    tlist_vinfo *vinfo;
    int            i;

    vinfo = itlist->vars;
    i = itlist->num_vars;
    while (i-- > 0)
    {
        if (vinfo->varno == varno && vinfo->varattno == varattno)
        {
            /* Found a match */
            Var           *newvar = copyVar(var);

            newvar->varno = newvarno;
            newvar->varattno = vinfo->resno;
            if (newvar->varnoold > 0)
                newvar->varnoold += rtoffset;
            return newvar;
        }
        vinfo++;
    }
    return NULL;                /* no match */
}

/*
 * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
 *
 * If a match is found, return a Var constructed to reference the tlist item.
 * If no match, return NULL.
 *
 * NOTE: it is a waste of time to call this unless itlist->has_ph_vars or
 * itlist->has_non_vars.  Furthermore, set_join_references() relies on being
 * able to prevent matching of non-Vars by clearing itlist->has_non_vars,
 * so there's a correctness reason not to call it unless that's set.
 */
static Var *
search_indexed_tlist_for_non_var(Expr *node,
                                 indexed_tlist *itlist, Index newvarno)
{
    TargetEntry *tle;

    /*
     * If it's a simple Const, replacing it with a Var is silly, even if there
     * happens to be an identical Const below; a Var is more expensive to
     * execute than a Const.  What's more, replacing it could confuse some
     * places in the executor that expect to see simple Consts for, eg,
     * dropped columns.
     */
    if (IsA(node, Const))
        return NULL;

    tle = tlist_member(node, itlist->tlist);
    if (tle)
    {
        /* Found a matching subplan output expression */
        Var           *newvar;

        newvar = makeVarFromTargetEntry(newvarno, tle);
        newvar->varnoold = 0;    /* wasn't ever a plain Var */
        newvar->varoattno = 0;
        return newvar;
    }
    return NULL;                /* no match */
}

/*
 * search_indexed_tlist_for_sortgroupref --- find a sort/group expression
 *        (which is assumed not to be just a Var)
 *
 * If a match is found, return a Var constructed to reference the tlist item.
 * If no match, return NULL.
 *
 * This is needed to ensure that we select the right subplan TLE in cases
 * where there are multiple textually-equal()-but-volatile sort expressions.
 * And it's also faster than search_indexed_tlist_for_non_var.
 */
static Var *
search_indexed_tlist_for_sortgroupref(Expr *node,
                                      Index sortgroupref,
                                      indexed_tlist *itlist,
                                      Index newvarno)
{
    ListCell   *lc;

    foreach(lc, itlist->tlist)
    {
        TargetEntry *tle = (TargetEntry *) lfirst(lc);

        /* The equal() check should be redundant, but let's be paranoid */
        if (tle->ressortgroupref == sortgroupref &&
            equal(node, tle->expr))
        {
            /* Found a matching subplan output expression */
            Var           *newvar;

            newvar = makeVarFromTargetEntry(newvarno, tle);
            newvar->varnoold = 0;    /* wasn't ever a plain Var */
            newvar->varoattno = 0;
            return newvar;
        }
    }
    return NULL;                /* no match */
}

/*
 * fix_join_expr
 *       Create a new set of targetlist entries or join qual clauses by
 *       changing the varno/varattno values of variables in the clauses
 *       to reference target list values from the outer and inner join
 *       relation target lists.  Also perform opcode lookup and add
 *       regclass OIDs to root->glob->relationOids.
 *
 * This is used in three different scenarios:
 * 1) a normal join clause, where all the Vars in the clause *must* be
 *      replaced by OUTER_VAR or INNER_VAR references.  In this case
 *      acceptable_rel should be zero so that any failure to match a Var will be
 *      reported as an error.
 * 2) RETURNING clauses, which may contain both Vars of the target relation
 *      and Vars of other relations. In this case we want to replace the
 *      other-relation Vars by OUTER_VAR references, while leaving target Vars
 *      alone. Thus inner_itlist = NULL and acceptable_rel = the ID of the
 *      target relation should be passed.
 * 3) ON CONFLICT UPDATE SET/WHERE clauses.  Here references to EXCLUDED are
 *      to be replaced with INNER_VAR references, while leaving target Vars (the
 *      to-be-updated relation) alone. Correspondingly inner_itlist is to be
 *      EXCLUDED elements, outer_itlist = NULL and acceptable_rel the target
 *      relation.
 *
 * 'clauses' is the targetlist or list of join clauses
 * 'outer_itlist' is the indexed target list of the outer join relation,
 *        or NULL
 * 'inner_itlist' is the indexed target list of the inner join relation,
 *        or NULL
 * 'acceptable_rel' is either zero or the rangetable index of a relation
 *        whose Vars may appear in the clause without provoking an error
 * 'rtoffset': how much to increment varnoold by
 *
 * Returns the new expression tree.  The original clause structure is
 * not modified.
 */
static List *
fix_join_expr(PlannerInfo *root,
              List *clauses,
              indexed_tlist *outer_itlist,
              indexed_tlist *inner_itlist,
              Index acceptable_rel,
              int rtoffset)
{
    fix_join_expr_context context;

    context.root = root;
    context.outer_itlist = outer_itlist;
    context.inner_itlist = inner_itlist;
    context.acceptable_rel = acceptable_rel;
    context.rtoffset = rtoffset;
    return (List *) fix_join_expr_mutator((Node *) clauses, &context);
}

static Node *
fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
{// #lizard forgives
    Var           *newvar;
	bool		converted_whole_row;

    if (node == NULL)
        return NULL;
    if (IsA(node, Var))
    {
        Var           *var = (Var *) node;

        /* Look for the var in the input tlists, first in the outer */
        if (context->outer_itlist)
        {
            newvar = search_indexed_tlist_for_var(var,
                                                  context->outer_itlist,
                                                  OUTER_VAR,
                                                  context->rtoffset);
            if (newvar)
                return (Node *) newvar;
        }

        /* then in the inner. */
        if (context->inner_itlist)
        {
            newvar = search_indexed_tlist_for_var(var,
                                                  context->inner_itlist,
                                                  INNER_VAR,
                                                  context->rtoffset);
            if (newvar)
                return (Node *) newvar;
        }

        /* If it's for acceptable_rel, adjust and return it */
        if (var->varno == context->acceptable_rel)
        {
            var = copyVar(var);
            var->varno += context->rtoffset;
            if (var->varnoold > 0)
                var->varnoold += context->rtoffset;
            return (Node *) var;
        }

        /* No referent found for Var */
        elog(ERROR, "variable not found in subplan target lists");
    }
    if (IsA(node, PlaceHolderVar))
    {
        PlaceHolderVar *phv = (PlaceHolderVar *) node;

        /* See if the PlaceHolderVar has bubbled up from a lower plan node */
        if (context->outer_itlist && context->outer_itlist->has_ph_vars)
        {
            newvar = search_indexed_tlist_for_non_var((Expr *) phv,
                                                      context->outer_itlist,
                                                      OUTER_VAR);
            if (newvar)
                return (Node *) newvar;
        }
        if (context->inner_itlist && context->inner_itlist->has_ph_vars)
        {
            newvar = search_indexed_tlist_for_non_var((Expr *) phv,
                                                      context->inner_itlist,
                                                      INNER_VAR);
            if (newvar)
                return (Node *) newvar;
        }

        /* If not supplied by input plans, evaluate the contained expr */
        return fix_join_expr_mutator((Node *) phv->phexpr, context);
    }
    if (IsA(node, Param))
        return fix_param_node(context->root, (Param *) node);

    /* Try matching more complex expressions too, if tlists have any */
	converted_whole_row = is_converted_whole_row_reference(node);
	if (context->outer_itlist &&
		(context->outer_itlist->has_non_vars ||
		 (context->outer_itlist->has_conv_whole_rows && converted_whole_row)))
    {
        newvar = search_indexed_tlist_for_non_var((Expr *) node,
                                                  context->outer_itlist,
                                                  OUTER_VAR);
        if (newvar)
            return (Node *) newvar;
    }
	if (context->inner_itlist &&
		(context->inner_itlist->has_non_vars ||
		 (context->inner_itlist->has_conv_whole_rows && converted_whole_row)))
    {
        newvar = search_indexed_tlist_for_non_var((Expr *) node,
                                                  context->inner_itlist,
                                                  INNER_VAR);
        if (newvar)
            return (Node *) newvar;
    }
    fix_expr_common(context->root, node);
    return expression_tree_mutator(node,
                                   fix_join_expr_mutator,
                                   (void *) context);
}

/*
 * fix_upper_expr
 *        Modifies an expression tree so that all Var nodes reference outputs
 *        of a subplan.  Also looks for Aggref nodes that should be replaced
 *        by initplan output Params.  Also performs opcode lookup, and adds
 *        regclass OIDs to root->glob->relationOids.
 *
 * This is used to fix up target and qual expressions of non-join upper-level
 * plan nodes, as well as index-only scan nodes.
 *
 * An error is raised if no matching var can be found in the subplan tlist
 * --- so this routine should only be applied to nodes whose subplans'
 * targetlists were generated by flattening the expressions used in the
 * parent node.
 *
 * If itlist->has_non_vars is true, then we try to match whole subexpressions
 * against elements of the subplan tlist, so that we can avoid recomputing
 * expressions that were already computed by the subplan.  (This is relatively
 * expensive, so we don't want to try it in the common case where the
 * subplan tlist is just a flattened list of Vars.)
 *
 * 'node': the tree to be fixed (a target item or qual)
 * 'subplan_itlist': indexed target list for subplan (or index)
 * 'newvarno': varno to use for Vars referencing tlist elements
 * 'rtoffset': how much to increment varnoold by
 *
 * The resulting tree is a copy of the original in which all Var nodes have
 * varno = newvarno, varattno = resno of corresponding targetlist element.
 * The original tree is not modified.
 */
static Node *
fix_upper_expr(PlannerInfo *root,
               Node *node,
               indexed_tlist *subplan_itlist,
               Index newvarno,
               int rtoffset)
{
    fix_upper_expr_context context;

    context.root = root;
    context.subplan_itlist = subplan_itlist;
    context.newvarno = newvarno;
    context.rtoffset = rtoffset;
    return fix_upper_expr_mutator(node, &context);
}

static Node *
fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
{// #lizard forgives
    Var           *newvar;

    if (node == NULL)
        return NULL;
    if (IsA(node, Var))
    {
        Var           *var = (Var *) node;

        newvar = search_indexed_tlist_for_var(var,
                                              context->subplan_itlist,
                                              context->newvarno,
                                              context->rtoffset);
        if (!newvar)
            elog(ERROR, "variable not found in subplan target list");
        return (Node *) newvar;
    }
    if (IsA(node, PlaceHolderVar))
    {
        PlaceHolderVar *phv = (PlaceHolderVar *) node;

        /* See if the PlaceHolderVar has bubbled up from a lower plan node */
        if (context->subplan_itlist->has_ph_vars)
        {
            newvar = search_indexed_tlist_for_non_var((Expr *) phv,
                                                      context->subplan_itlist,
                                                      context->newvarno);
            if (newvar)
                return (Node *) newvar;
        }
        /* If not supplied by input plan, evaluate the contained expr */
        return fix_upper_expr_mutator((Node *) phv->phexpr, context);
    }
    if (IsA(node, Param))
        return fix_param_node(context->root, (Param *) node);
    if (IsA(node, Aggref))
    {
        Aggref       *aggref = (Aggref *) node;

        /* See if the Aggref should be replaced by a Param */
        if (context->root->minmax_aggs != NIL &&
            list_length(aggref->args) == 1)
        {
            TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
            ListCell   *lc;

            foreach(lc, context->root->minmax_aggs)
            {
                MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);

                if (mminfo->aggfnoid == aggref->aggfnoid &&
                    equal(mminfo->target, curTarget->expr))
                    return (Node *) copyObject(mminfo->param);
            }
        }
        /* If no match, just fall through to process it normally */
    }
    /* Try matching more complex expressions too, if tlist has any */
	if (context->subplan_itlist->has_non_vars ||
		(context->subplan_itlist->has_conv_whole_rows &&
		 is_converted_whole_row_reference(node)))
    {
        newvar = search_indexed_tlist_for_non_var((Expr *) node,
                                                  context->subplan_itlist,
                                                  context->newvarno);
        if (newvar)
            return (Node *) newvar;
    }
    fix_expr_common(context->root, node);
    return expression_tree_mutator(node,
                                   fix_upper_expr_mutator,
                                   (void *) context);
}

/*
 * set_returning_clause_references
 *        Perform setrefs.c's work on a RETURNING targetlist
 *
 * If the query involves more than just the result table, we have to
 * adjust any Vars that refer to other tables to reference junk tlist
 * entries in the top subplan's targetlist.  Vars referencing the result
 * table should be left alone, however (the executor will evaluate them
 * using the actual heap tuple, after firing triggers if any).  In the
 * adjusted RETURNING list, result-table Vars will have their original
 * varno (plus rtoffset), but Vars for other rels will have varno OUTER_VAR.
 *
 * We also must perform opcode lookup and add regclass OIDs to
 * root->glob->relationOids.
 *
 * 'rlist': the RETURNING targetlist to be fixed
 * 'topplan': the top subplan node that will be just below the ModifyTable
 *        node (note it's not yet passed through set_plan_refs)
 * 'resultRelation': RT index of the associated result relation
 * 'rtoffset': how much to increment varnos by
 *
 * Note: the given 'root' is for the parent query level, not the 'topplan'.
 * This does not matter currently since we only access the dependency-item
 * lists in root->glob, but it would need some hacking if we wanted a root
 * that actually matches the subplan.
 *
 * Note: resultRelation is not yet adjusted by rtoffset.
 */
static List *
set_returning_clause_references(PlannerInfo *root,
                                List *rlist,
                                Plan *topplan,
                                Index resultRelation,
                                int rtoffset)
{
    indexed_tlist *itlist;

    /*
     * We can perform the desired Var fixup by abusing the fix_join_expr
     * machinery that formerly handled inner indexscan fixup.  We search the
     * top plan's targetlist for Vars of non-result relations, and use
     * fix_join_expr to convert RETURNING Vars into references to those tlist
     * entries, while leaving result-rel Vars as-is.
     *
     * PlaceHolderVars will also be sought in the targetlist, but no
     * more-complex expressions will be.  Note that it is not possible for a
     * PlaceHolderVar to refer to the result relation, since the result is
     * never below an outer join.  If that case could happen, we'd have to be
     * prepared to pick apart the PlaceHolderVar and evaluate its contained
     * expression instead.
     */
    itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);

    rlist = fix_join_expr(root,
                          rlist,
                          itlist,
                          NULL,
                          resultRelation,
                          rtoffset);

    pfree(itlist);

    return rlist;
}


/*****************************************************************************
 *                    QUERY DEPENDENCY MANAGEMENT
 *****************************************************************************/

/*
 * record_plan_function_dependency
 *        Mark the current plan as depending on a particular function.
 *
 * This is exported so that the function-inlining code can record a
 * dependency on a function that it's removed from the plan tree.
 */
void
record_plan_function_dependency(PlannerInfo *root, Oid funcid)
{
    /*
     * For performance reasons, we don't bother to track built-in functions;
     * we just assume they'll never change (or at least not in ways that'd
     * invalidate plans using them).  For this purpose we can consider a
     * built-in function to be one with OID less than FirstBootstrapObjectId.
     * Note that the OID generator guarantees never to generate such an OID
     * after startup, even at OID wraparound.
     */
    if (funcid >= (Oid) FirstBootstrapObjectId)
    {
        PlanInvalItem *inval_item = makeNode(PlanInvalItem);

        /*
         * It would work to use any syscache on pg_proc, but the easiest is
         * PROCOID since we already have the function's OID at hand.  Note
         * that plancache.c knows we use PROCOID.
         */
        inval_item->cacheId = PROCOID;
        inval_item->hashValue = GetSysCacheHashValue1(PROCOID,
                                                      ObjectIdGetDatum(funcid));

        root->glob->invalItems = lappend(root->glob->invalItems, inval_item);
    }
}

/*
 * extract_query_dependencies
 *        Given a rewritten, but not yet planned, query or queries
 *        (i.e. a Query node or list of Query nodes), extract dependencies
 *        just as set_plan_references would do.  Also detect whether any
 *        rewrite steps were affected by RLS.
 *
 * This is needed by plancache.c to handle invalidation of cached unplanned
 * queries.
 */
void
extract_query_dependencies(Node *query,
                           List **relationOids,
                           List **invalItems,
                           bool *hasRowSecurity)
{
    PlannerGlobal glob;
    PlannerInfo root;

    /* Make up dummy planner state so we can use this module's machinery */
    MemSet(&glob, 0, sizeof(glob));
    glob.type = T_PlannerGlobal;
    glob.relationOids = NIL;
    glob.invalItems = NIL;
    /* Hack: we use glob.dependsOnRole to collect hasRowSecurity flags */
    glob.dependsOnRole = false;

    MemSet(&root, 0, sizeof(root));
    root.type = T_PlannerInfo;
    root.glob = &glob;

    (void) extract_query_dependencies_walker(query, &root);

    *relationOids = glob.relationOids;
    *invalItems = glob.invalItems;
    *hasRowSecurity = glob.dependsOnRole;
}

static bool
extract_query_dependencies_walker(Node *node, PlannerInfo *context)
{// #lizard forgives
    if (node == NULL)
        return false;
    Assert(!IsA(node, PlaceHolderVar));
    /* Extract function dependencies and check for regclass Consts */
    fix_expr_common(context, node);
    if (IsA(node, Query))
    {
        Query       *query = (Query *) node;
        ListCell   *lc;

        if (query->commandType == CMD_UTILITY)
        {
            /*
             * Ignore utility statements, except those (such as EXPLAIN) that
             * contain a parsed-but-not-planned query.
             */
            query = UtilityContainsQuery(query->utilityStmt);
            if (query == NULL)
                return false;
        }

        /* Remember if any Query has RLS quals applied by rewriter */
        if (query->hasRowSecurity)
            context->glob->dependsOnRole = true;

        /* Collect relation OIDs in this Query's rtable */
        foreach(lc, query->rtable)
        {
            RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);

            if (rte->rtekind == RTE_RELATION)
                context->glob->relationOids =
                    lappend_oid(context->glob->relationOids, rte->relid);
            else if (rte->rtekind == RTE_NAMEDTUPLESTORE &&
                     OidIsValid(rte->relid))
                context->glob->relationOids =
                    lappend_oid(context->glob->relationOids,
                                rte->relid);
        }

        /* And recurse into the query's subexpressions */
        return query_tree_walker(query, extract_query_dependencies_walker,
                                 (void *) context, 0);
    }
    return expression_tree_walker(node, extract_query_dependencies_walker,
                                  (void *) context);
}


/*
 * is_converted_whole_row_reference
 *     If the given node is a ConvertRowtypeExpr encapsulating a whole-row
 *     reference as implicit cast, return true. Otherwise return false.
 */
static bool
is_converted_whole_row_reference(Node *node)
{
   ConvertRowtypeExpr *convexpr;

   if (!node || !IsA(node, ConvertRowtypeExpr))
       return false;

   /* Traverse nested ConvertRowtypeExpr's. */
   convexpr = castNode(ConvertRowtypeExpr, node);
   while (convexpr->convertformat == COERCE_IMPLICIT_CAST &&
          IsA(convexpr->arg, ConvertRowtypeExpr))
       convexpr = castNode(ConvertRowtypeExpr, convexpr->arg);

   if (IsA(convexpr->arg, Var))
   {
       Var *var = castNode(Var, convexpr->arg);

       if (var->varattno == 0)
           return true;
   }

   return false;
}

#ifdef XCP
/*
 * set_remotesubplan_references
 *    Usually RemoteSubplan node does just translates its target list, so it is
 * enought to invoke fix_scan_list here. One exception is if the
 * RemoteSubplan is set on top of ModifyTable. In this case target lists of both
 * these plan nodes are NIL. If the subplan is not returning we want to leave
 * target list NIL, if yes, we should make up target list as a list of simple
 * references to entries from the first returning list.
 * The qual of RemoteSubplan is always NULL.
 */
static void
set_remotesubplan_references(PlannerInfo *root, Plan *plan, int rtoffset)
{
    if (plan->targetlist == NIL)
    {
        ModifyTable *mt = (ModifyTable *) plan->lefttree;
        if (IsA(mt, ModifyTable) && mt->returningLists)
        {
            List        *returningList;
            List       *output_targetlist;
            ListCell   *l;

            returningList = (List *) linitial(mt->returningLists);
            output_targetlist = NIL;
            foreach(l, returningList)
            {
                TargetEntry *tle = (TargetEntry *) lfirst(l);
                Var           *newvar;

                newvar = makeVar(OUTER_VAR,
                                 tle->resno,
                                 exprType((Node *) tle->expr),
                                 exprTypmod((Node *) tle->expr),
                                 exprCollation((Node *) tle->expr),
                                 0);
                if (IsA(tle->expr, Var))
                {
                    newvar->varnoold = ((Var *) tle->expr)->varno + rtoffset;
                    newvar->varoattno = ((Var *) tle->expr)->varattno;
                }
                else
                {
                    newvar->varnoold = 0;        /* wasn't ever a plain Var */
                    newvar->varoattno = 0;
                }

                tle = flatCopyTargetEntry(tle);
                tle->expr = (Expr *) newvar;
                output_targetlist = lappend(output_targetlist, tle);
            }
            plan->targetlist = output_targetlist;
        }
    }
    else
    {
        /*
         * The RemoteSubplan may look like a subject for a dummy tlist.
         * It works in most cases. However it may be a subplan of a ModifyTable
         * running against a relation with dropped columns. Sanity check assumes
         * that subplan will return a NULL constant as a value for the dropped
         * column, however set_dummy_tlist_references would replace it with a
         * Var. We cannot detemine the parent plan here, so just process it as
         * a scan. Executor will ignore this anyway.
         */
        plan->targetlist = fix_scan_list(root, plan->targetlist, rtoffset);
    }
    Assert(plan->qual == NULL);
}
#endif
